I'm a lung shooter but normally hold between C and D. Just under halfway up. I rarely find the heart hit when I gut them out, and if it has been hit it was because I misjudged the drop or pulled the shot a bit. Probably the archer in me, as getting both lungs with an arrow has given me excellent results time and again. Quartering away I just hold back on the ribs where I need to to get it to go through the vitals, I don't try to line up with the offside leg normally because if it is way forward or back it can give a poor angle and in the excitement of the moment it can be something a person forgets to check on. To me it is quicker/easier to just "see" where the hold needs to be so it goes through the center of the lung area. Quartering to shots are really the same, I just hold where I need to so the projectile goes through the center of the lung area. I normally won't take a straight on shot, as I hate turning the stomach contents into soup and a liquefied mess when gutting them. Straight away I will only take if they are looking back and I'm confident I can hit the neck, such as I have a rest or it is a pretty close shot.
SDSmlf, I've encountered a handful of people that shot animals without thinking about the terrain or where they were. Some of them were a true "you're only getting to eat that if you take a lighter, fork, and knife with you and eat it on the spot". Normally the only true chance at salvaging the meat is to bone it out as soon as you can get to the animal, but few seem to be willing to go that route and rarely have a pack frame to carry it out.